class Solution {
public:
    vector<int> twoSum(vector<int>& numbers, int target) {
        int low = 0, high = numbers.size() - 1;
        while (low < high) {
            int sum = numbers[low] + numbers[high];
            if (sum == target) {
                return { low + 1, high + 1 };
            }
            else if (sum < target) {
                ++low;
            }
            else {
                --high;
            }
        }
        return { -1, -1 };
    }
};

